There are some Swedish that have it, some South Americans that have it, some bantam Cochins spontaneously developed it (Bantam Barn- Steve Wheat has them!), and they appear in Ayam Cemani occasionally. I know there are also Seramas with it. I'm sure there are more, but those are all I know of off of the top of my head.OK!! I didn't realize that a "silkied" chicken was a pure bred of whatever breed (in your case...silkied AM's) that just had recessive genes for hookless feathers. I thought "silkied" chicks were bred from crossing a Silkie into the bloodline of your chickens to get the h gene incorporated. Are hookless feathers a common gene mutation? I thought that Silkies were the only chickens with hookless feathers...sorry, but I am even still lerning more!
It's pretty wild to have a larger bird than a Silkie...definitely more like fur than feathers!!